Founder Species - Why the Fermi Paradox is Wrong

[The Reaver of Darkness]

This is a slightly off-topic article that relates to my introspecion on the origin of the alien intelligence(s) that have visited Earth. First, I begin with explaining just how rapidly we showed up, and how the universe may yet blossom full of life but it may simply be too young to be covered with interstellar civilizations.


The Fermi Paradox states that our own galaxy has got to have millions of life-supporting planets around stars some of which are older than our sun, and some of those planets would likely produce alien civilizations which could traverse the Milky Way in millions of years even without faster-than-light travel. The paradox is that despite all the time that has passed (the universe is ~13.8 billion years old), we see no evidence of extraterrestrial intelligence.

I think 14 billion years is a bit early to start saying there's nobody out there.



Let's start with a list of the things a life-supporting planet needs to produce a civilization--and I'm going to use a modern and loose-fitting set of needs which may differ from the necessary things you've heard about:
1.) nutrients for biochemistry - the planet's surface must be rich in substances that can create biochemical molecules. This probably means hydrogen, carbon, nitrogen, and oxygen and fortunately these are extremely abundant. They are also low density and so are likely to be found on the surface of the planet.
2.) an atmosphere to allow liquids and gases on the surface, many of which are important for biochemical interactions. Many planets form with an atmosphere but most lose it eventually.
3.) a stable environment that allows life to evolve for a long time without the planet becoming sterilized at any point.

You may have heard that planets have to be the exact right distance from their star, the 'Goldilocks Zone' if you will. That zone is actually a rather thick band, for instance in our solar system Venus, Earth, and Mars are all within this Goldilocks Zone. Venus and Mars are inhospitable because they don't have a strong magnetic field. Earth's magnetic field is constantly reinforced by the strong tidal forces between it and its large moon. Venus and Mars don't have a large moon. Once upon a time they both had flowing water on their surface and may both have had simple life.

The Downfall of Venus: This planet is Earth's twin, it's barely smaller and has about the same internal makeup, being made of mostly iron. It probably started off with a strong magnetic field and a moderately-thick atmosphere of primarily hydrogen. But over time its mantle cooled and began to stop moving, and its magnetic field waned. Its atmosphere bled into space and some event (seems to be connected to the loss of magnetic field) triggered intense volcanism which caused the surface to continually spew out tons of carbon-dioxide gas. Today the planet has a very thick atmosphere which is constantly being bled into space but is also being constantly renewed by the intense volcanism.

The Downfall of Mars: This planet is significantly smaller but still quite large enough to support life. Its internal makeup is low on iron, being much more carbon-rich and giving the planet a much lower gravitational pull than Earth. It probably had an atmosphere of primarily hydrogen initially, and it definitely had flowing water on its surface. We can see the evidence of this all over the surface: it is covered in lake beds, river chasms, deltas, oxbow lakes, and everything in between. But the mantle and core began to cool and it lost nearly all of its magnetic field. The low density composition of Mars and its lack of heavy radioisotopes likely made its core cool even faster, causing the magnetic field to wane more rapidly. It is possible Mars also went through a phase of intense volcanism--today we see giant volcanoes on its surface much like Venus has, but the ones on Mars are long dead and the atmosphere of carbon dioxide has grown very thin. The only thing keeping it from completely escaping into space is that some of the carbon dioxide keeps freezing onto the poles, and melting again. This delays its escape, but it's only a matter of time before Mars' surface is a vacuum. Eventually Venus will follow.

Why the Earth thrives: Earth has a strong magnetic field which holds in its atmosphere. This magnetic field is constantly replenished by internal motion and shear forces in the supersolid mantle. This mantle is technically solid and we can determine this by sending sound waves through it. The sound waves are blocked by the liquid core. The mantle is so hot that the rocky iron-rich material it's made of should be liquid or gas, but it's under so much pressure that it's solid. The pressure is so great, in fact, that these solids are deformed and pushed around almost like a liquid. The mantle ebbs and flows like a giant ocean of solid rock, creating tremendous frictional forces and magnetizing the planet as a whole. What keeps it hot is a twofold effort: the giant moon's tidal forces rip and tear the crust and mantle, generating heat near the surface, while the radioisotopes within the core decay gradually and produce heat from within. The mantle can't cool because it's being heated from both sides.



So how often can we expect to find a planet like Earth, with all those heavy metals and a large moon? The answer is less about rarity and more about time. When the universe first formed, it expanded rapidly but it took a very long time before it had cooled enough for matter to form. After about 150 million years, stars of pure hydrogen began to form, and we call these Population 3 stars. There were no heavy metals in these stars initially. Elements from helium to carbon can be produced in a small/main sequence star (like our sun) and after it fuses carbon in its core, it becomes unstable and sheds its outer layers in what we call a nova, trapping everything heavier than helium in its white dwarf core.

The metal gets outside of the stars by way of supernovae. These are caused by giant stars fusing all the way up to iron, which causes them to explode violently. The lithium through iron in the core still is trapped inside and the core becomes either a neutron star or a black hole, but the ejecta is released with such tremendous force that much of it is fused into the really heavy elements, and this is where most of the elements, such as gold or uranium are produced.

Most stars were stable for a long time, but some lived short lives and exploded young. Size was a big factor here, larger stars didn't last as long, but density was another factor. The lightweight population 3 stars burnt their fuel much slower than the majority of stars today, and so there was a long time before even population 2 stars became abundant. Population 3 stars would not have had any planets, but may have had other stars orbiting them.

It's hard to say when population 2 stars started to pop up, but gradually as stars exploded and new ones formed, some stars got heavier elements inside of them. These were the population 2 stars, containing heavier elements, but they were still very metal-poor compared to the population 1 stars that are abundant today. These population 2 stars may have had a few sparse bits of debris orbiting them, and they may have captured planets later, but overall they would be barren. They played an important role, however, as they would go through their life much faster and explode, enriching the universe with more metals so that eventually population 1 stars could form.

It was about a billion years after the Big Bang that galaxies began to form, and around the same time that the very last population 3 stars formed. Any population 3 stars (extremely metal poor) alive today are almost certainly over 13 billion years old, and many of them may stick around quite a bit longer as they very slowly burn through their fuel. By the time galaxies began to form, metals and heavier elements were spread all over the universe, albeit still in small amounts. Many population 2 stars formed, and gradually seeded the universe with more metals.

Around 4-5 billion years after the Big Bang, the first population 1 stars formed, rich (relatively speaking) with metals (astronomical term for all heavier elements) and these probably had planets around them. The first population 1 stars were as yet metal poor compared to what life needs, but early star systems could have had a variety of lifeless planets orbiting them. Maybe life started on a few of these, but it probably didn't get very far as those planets probably didn't have atmospheres, and the few that did would have lost them quickly without a magnetic field. This was around 10 billion years ago.

The oldest metal-rich population 1 stars formed around 7 billion years ago, 7 billion years after the Big Bang, when the universe was half the age it is now. These stars had rich accretion disks which would have given them an abundance of planets, some of which would be very large and have very thick layers of gases, compressed into deep oceans made of mostly hydrogen and helium. These are what we call gas giants or ice giants, depending on their exact composition. Don't let the name fool you, they're mostly liquid. Names in astrophysics tend to refer more to their composition relative to other objects, than it does to their specific traits.





Now we've finally got the first stars that can bear life-supporting planets, and it only took 7 billion years. From here, it's a matter of chance whether or not life gets off to a good start. It'll need a metal-rich planet--not necessarily as rich as Earth--I simply mean not a barren chunk of lithium. It's going to need to be rich in carbon, oxygen, and nitrogen, and it wouldn't hurt to have a heavier core to push all the lighter stuff up to the surface. It also needs a large moon and a protective gas giant. The gas giant provides that stable environment I mentioned earlier, ensuring that this rich accretion disk doesn't become a shooting gallery and prevent the planet from stabilizing before it's lost its chance to start life. But gas giants are abundant around these stars, so that doesn't eliminate too many. The biggest factor of chance here is getting that moon. They're rare because planets can't form with a moon like that--it would have been unstable during accretion and they would have merged. The only way for a planet to have a large moon is for it to gain the moon after accretion.

Earth seems to have obtained its moon when the Mars-sized planet Theia plunged sidelong into the Earth, merging the two and sending a large amount of material into a low orbit around the Earth. This likely happened about 4.5 billion years ago, perhaps only a hundred million years after the Earth formed and within the first billion years after our sun and solar system began to form. The material pushed into Earth's orbit would have coalesced into the moon we see today--built out of the same stuff as our planet, but barren because it lacks the heavy core. It became tidally locked with Earth and cooled, losing its magnetic field and atmosphere. Its core is probably completely solid. But it keeps us alive today.

Another possible way to obtain a large moon in a low orbit is for one to be captured into the planet's orbit. It would initially have a highly elliptical orbit, but close encounters with other bodies in the young star system would adjust its orbit until either it becomes stable, is ejected, or crashes into something. There may be other possible ways to obtain a large moon, but the vast majority of times it'll happen are in one of these two ways.

The chance of your protected planet in the Goldilocks Zone obtaining a large moon are slim. Most planets in the accretion disk never get struck by another planet, and the ones that do aren't likely to get a moon from it. If the planet hits too directly, they may shatter each other or just merge together, which one depending on the speed of the impact. If the planet hits a glancing blow, they may both keep on going, losing very little matter yet having their orbits readjusted. And if the planet does hit at a good angle, it may send the other planet reeling off on a bad orbit that might lead to it colliding with another planet or being ejected from the star system. The same poor chances exist for those rare planets that capture a large moon, for it has to become stabilized before it either gets ejected or collides with its new parent planet. It's like playing Russian Roulette every time you flip a coin until it lands on its edge.

But somewhere out there it's bound to happen. Still, that means it probably isn't very common in the early universe. But not very common 7 billion years ago would be far more common today, given how rich our galaxies are in population 1 stars. So that brings in the question: how long does life need to produce a space-colonizing civilization? Well let's walk through the Earth's development. It's 4.5 billion years ago, chance happened, Jupiter defends us, we got a large moon, and we've definitely got the materials for life to form. Now it's once again a waiting game.





The moon cools and the planet's surface cools. The moon was much closer to the surface than it is today, and it wasn't tidally locked. It created intense tidal forces, but the Earth's surface was able to cool enough for life to form. The hydrogen atmosphere acted as a weak shielding from the sun's ionizing cosmic rays, but life needed more shielding than that. The surface was probably a bit moist, but rocky, barren. No life formed yet.

Over the next hundred million years or so, the planet was bombarded repeatedly with smaller meteors and comets, and they may have enriched it with more water. One way or another, nearly all of the water it has today was probably on the planet within the first few hundred million years after it formed. Over time the impacts began to thin out, oceans formed, and within some of the warm, shallow waters complex molecules began to form. They probably came together quickly as soon as conditions were right. The oxygen and nitrogen would have readily combined with other materials to form many simple organic compounds. Carbon could form long chain molecules, allowing for many kinds of chemistry to happen. Water was the solvent and catalyst, mixing the reagents and driving them to form new compounds. And lightning provided ionization, splitting apart overly stable compounds and enabling special compounds to form which could not form in the absence of electrical ionization.

RNA and DNA formed in these oceans and it began to replicate itself, kicking off the process of evolution by gene mutation and natural selection. This all happened in the early years of the Earth, more than 4 billion years ago, and only maybe 1-2 hundred million years after Earth stabilized and became suitable for life. All life we have found on Earth is genetically related, suggesting that while life may have started multiple times on Earth and in multiple places, only one set ever survived to today. Some say it was the extremely lucky strain that didn't die to whatever killed the rest, but I don't believe that for a moment. I'll bet it gained a strong mutation and conquered all other life on the planet, rendering it extinct. During this time, meteor impacts may have sent life off the Earth and into space, where it is conceivable it may have survived and later impacted Mars or Venus. They, too, may have had life ejected into space where it landed on Earth. Maybe all life on Earth originated on Venus or Mars. Maybe the tough strains that survived space travel became the invasive species that killed off everything else. We don't know. But today Venus and Mars are hostile and we think probably lifeless while life on Earth thrives.

Eventually the DNA and RNA gained cellular bubbles which protected them while allowing genetic material and important nutrients to pass through the porous shell. These were the first cells and most of us say it was the first life, but I say life began at DNA creation. Where you draw the line is moot, however. But after this, single-celled prokaryotic bacteria (the first and most successful domain of life) thrived and began to fill the shallow parts of the Earth's oceans. They lived around 1-100 meters beneath the surface, deep enough to be protected from the sun but shallow enough to receive its warmth, shallow enough for ocean currents to churn up precious nutrients to sustain them. These first life consumed raw nutrients to sustain themselves and were not sufficiently developed to produce energy.

[The Reaver of Darkness]

Today we look at the fossil record and find the earliest multicellular life appearing around 2.5 billion years ago, while complex animals and plants didn't show up much until around 600 million years ago. Most people imagine life on Earth was sitting around as microbes, doing nothing and not changing very much, but the reality is that life went through many stages that made these complex animals and plants possible. It is unknown to us what changes life went through in the first billion years after Earth's formation but undoubtedly many things happened, and many important gene mutations were made. We can't study it very well because all of the fossils are gone, all of the rocks that existed back then have been molten and reformed at some point. The oldest rocks on Earth date back to anywhere from 2.5 to 3.8 billion years ago.

Around 3.5 billion years ago was an event for which we do have evidence. Cyanobacteria probably formed for the first time then, because oxygen began to appear in the rocks. These cyanobacteria were probably a different color, unlike the green cyanobacteria we have today, and this was due to a different bio-molecular process used in photosynthesis of energy storage. They used carbon dioxide and water to make sugars and oxygen, using the energy from the sun to fuel the process. The poisonous oxygen was a waste product which they emitted as dioxygen gas (O2). This gas did not remain in the atmosphere for long, as it would form compounds with the surface materials on dry land. Land was barren at this time, and covered in unreacted compounds that would eventually all be oxidized.

For the next ~1 billion years, oxygen continued to be emitted by cyanobacteria and absorbed by the dry land, and these cyanobacteria were hugely successful, covering the oceans and dominating nearly all of the biosphere at the time. But around 2 billion years after the Earth formed, about 2.5 billion years ago, the dry land became fully saturated with oxygen, and oxygen began to build up in the atmosphere. Life then lived entirely in the water and that offered it some protection, but as the oxygen built up in the atmosphere, it began to build up in the ocean as well. No more than 200 million years later, there was a great oxygen crisis. Living things evolved to resist oxygen, but there was simply a limit to how strong a concentration they could withstand. Some species took to living in moist soil or in vents or other places were they were safe from oxygen, and some became multicellular. But most life went extinct.

The jump to multicellular life was a huge leap. We think the way it happened was a larger cell consumed a smaller cell but the smaller cell was still alive inside it and the smaller cell just so happened to be an oxygen consumer but even still the smaller cell needed to be inside the larger cell to protect it and the larger cell had the oxygen levels inside its body reduced by the presence of the smaller cell consuming the oxygen. Yeah, it doesn't sound like an event that's likely to happen a lot. But there were trillions of bacteria out there and anything that didn't find some strategy like that died out, so at some point it happened. These were the first eukaryotes and we sometimes call them single-celled organisms but they have cells within their cells. They were a new domain of life.

The first truly multicellular life originated roughly around 1.5 billion years ago and developed slowly, but it was finally possible for large colonies of cells to live together. Cyanobacteria paved the way for food production and storage, eukaryotes made life with oxygen possible, and some time later the oxygen-consuming ancestors of mitochondria opened up a new much more efficient fuel source: oxygen. These first cellular colonies had different cells specialized into different functions, though early on they were little more than a mat of cells and each individual only contributed to the whole insomuch as it directly reaped the benefits for itself.

Over time these communities became more specialized, allowing for the complex development of organ structures. This enabled living things to get larger. Around 600 million years ago was the Cambrian Explosion, in which complex multicellular plants and animals suddenly began to appear all over the oceans, but let's back up a bit. Maybe as much as a billion years ago there were complex organisms that pre-dated plants and animals. We can't find very many fossils from this period because they all had soft bodies, but perhaps they were something like the rangeomorphs which lived 600 million years ago. At some point in this time, sexual reproduction evolved and became common for some kinds of life.

It was in this time period that purple cyanobacteria covered the oceans and caused the planet's temperature to drop. This was the greatest major glaciation and the ice may have at times covered the entire Earth. Green cyanobacteria evolved at this time, using a new molecule, chlorophyll, to produce energy through photosynthesis. These new green cyanobacteria were much more successful in the freezing temperatures and may have assisted in melting the ice and letting the Earth warm again. This "Snowball Earth" was also a major extinction event and most of the life on the planet went extinct. Emerging from this was new, more complex life, with more strategies to survive in tough circumstances. Plants evolved from green cyanobacteria, and animals evolved from motionless but sexually-reproducing colonial organisms.

So around 600 million years ago, the first animals and plants were evolving. Around 540 million years ago began the Cambrian Explosion, in which large and complex plants and animals first appeared. For the first time, it was possible to have large animals with organ structures throughout their body, highly specialized to perform specific roles in the function of the creature as a whole. These animals did not have brains as we would recognize them today, and operated on very simple principles. Their sensory organs were barely developed, and they moved slowly through the water, eating any unlucky living thing they came across. Over time and through a lot of selective pressures, they began to develop better locomotion, advanced senses, brains, and instincts. They began to choose their prey and specialize to capture that prey as effectively as possible.

Around 440 million years ago was a major extinction event that killed off around 60% of marine species. Shortly after this, complex life began to colonize land. First algae-like plants formed on the shores and eventually they spread to develop the predecessors of ferns. During this time bony fish and insects were also developing, and insects soon began to colonize the land, while bony fish remained a relatively insignificant prey animal. Their bony jaws were extremely useful, however.

Around 350 million years ago, vast forests were forming on land. There were a wide variety of arthropods on land and oxygen levels were rising quickly, enabling the arthropods to get very large. The first vertebrates came on land during this time, descendants of fish. For millions of years these trees grew out of control, for there were no micro-organisms in the soil to consume their enormous trunks when they finally fell. Trees littered the forest floor, weathering into dust and creating a thick layer of carbon-rich soil, and this is where the vast majority of today's fossil fuels come from. It's dead trees. It became to much, the trees lived too long and grew too large, and the Earth's oxygen levels rose too high, until wildfires began to break out like, well, wildfire. Forests were devastated but out of this came more soil microorganisms to break down all of the waste products created by dead plants and animals.

Animals already had some kinds of bacteria in their guts to assist with the digestion of food, but it took a long time for them to gain the very diverse range of bacteria which we have today. This is important, for all of these bacteria play a role within us, and they are part of how we are as complex as we are today. Around 250 million years ago, animals started to develop like the animals we see today, vertebrates on land with large brains. They formed the first reptiles and later branched off into mammals and dinosaurs. Even then, the majority of land life was simple and slow by today's standards. They had brains but they weren't intelligent. The first intelligent life on Earth probably appeared around 100-150 million years ago, and it was mammals, dinosaurs, and cephalopods. A major extinction event killed off the majority of dinosaur diversity but today an avian lineage remains which we know as birds. Even through the past 250 million years, the various trying times life has come across have shaped us. Animals didn't become intelligent very easily, but they were pushed that way through many different events, and it took many stages of development before their brains were so complex that they could assess their environment and make strategic decisions that weren't pre-programmed into them.

Even then, we humans didn't just spring out of this diversity of intelligence. We needed more than that. We needed advanced communication skills and the ability to pass on our knowledge to each next generation. We were an apex predator dethroned, a resourceful species thrust into a new environment, and we had to adapt. Most importantly, we had to be capable of adapting. That's what made us possible, and I don't think it could have happened much faster than it did.



So maybe there are lots of life-bearing worlds out there today, but they are probably younger than our world for the most part. Even today there aren't a lot of stars with both high metallicity and being at least 3-4 billion years old. Just look at the stars closest to us. We can ignore most of them because they are too small, unstable, or have other major problems. But the nice-sized ones have other problems:
Epsilon Eridani - a bit small, good metallicity...but it's only 400-800 million years old.
Procyon - good size, low metallicity, no stable orbit in habitable zone due to white dwarf companion. Oh and it's only ~1.5 billion years old.
61 Cygni - actually two stars, but they are about 6 billion years old, have good metallicity and are separated enough from each other to have stable life-supporting planets. What's the catch? They're swinging rapidly through the galaxy. They're not in orbit with the rest, and over time they're bound to go all sorts of places. That's bad, because large amounts of the galaxy are dangerous to life. That pair of stars has probably been through enough supernova remnants to cleanse its surface multiple times.
Epsilon Indi - good size, low metallicity, and it's only 1.3 billion years old.
Tau Ceti - about the same size as our Sun, good metallicity, about 5.8 billion years old, no companion stars. First good candidate at a glance and we're already 12 light years away.

Maybe life started on one of Tau Ceti's planets. If they were lucky, maybe they lasted for over a billion years before their planet destabilized. Even then, I doubt they progressed along as fast as we did. I think life on Earth got just the pushes it needed at just the right times. I'll bet most technology-developing species take over 8 billion years to evolve. So it might be a while before the animals on Tau Ceti III produce a creature we can meet up with in space.

I think we're a founder race. I think we'll be the ones to step out there and spread out across the stars. I think when other species look up and wonder how much life is out there, they'll develop sophisticated equipment to check, and they'll find us.

[Meridian]

Nice reading... definitely worth the time... and you might be right about the founder race.

However, RNG (or luck as we call it) works in mysterious ways and although it seems unimaginable for us that something could take a lot less time than we think, RNG always proves us wrong.

[The Reaver of Darkness]

However, RNG (or luck as we call it) works in mysterious ways and although it seems unimaginable for us that something could take a lot less time than we think, RNG always proves us wrong.

For sure. I don't doubt for a second that there are already vast intergalactic civilizations out there. But I'll bet untouched sectors are more than commonplace.

[Yankes]

Great read

btw about Jupiter and Saturn. Why our solar system look like and why its different than other than we see around (Hot jupiters or super earths close to stars)?
Simply because Jup and Sat murdered everyone during they voyage close to sun. We are only remnants of that left after they party

[The Reaver of Darkness]

btw about Jupiter and Saturn. Why our solar system look like and why its different than other than we see around (Hot jupiters or super earths close to stars)?

Massive planets close to their stars are the easiest to find. They aren't likely very common, but they're probably not particularly rare. Accretion disks will vary greatly in size, and this means the largest planets can be anywhere from right next to their stars to way out on the edges of the formed part of the system.

We're getting close to finding planets of Earth size within the habitable zone of a star. The James Webb space telescope will help greatly with this, and shortly after it's launched, we will most likely see a flood of Earth analogues coming in. We might even be able to determine their base makeup. We won't be able to check for the presence of large moons, but chemical makeup scans might reveal atmospheric composition, and that can let us in on just how stable it is.

[The_Funktasm]

I have never really liked the Fermi paradox. A good example on earth is that there are animals and peoples still undocumented. Now by the logic of the Fermi paradox they most likely don't exist on the basis that they'd have been seen already because we and them share space. Is it that hard for some scientists to think or project a little as to why aliens would not come into contact with us? (assuming they haven't, that's my other problem with the paradox)

Like off the top of my head, there's the possibility that aliens are just as paranoid about microbes and disease as we are. There's the possibility that they have a religious or philosophical reason to remain isolationist. There's the possibility that they've done everything BUT space-travel as far as technology. There's the possibility their society collapsed. There's the possibility that they're on their way right now even though it'll require a multigenerational or sleep ship with an eta of around another millennium or so. On top of that, if you could visit any species in the universe, would you pick us, if there were a list? Whether technologically or socially we just might not be worth talking to.

You brought up a really good possibility I haven't heard before, though. People, even scientists with their huge egos, will happily disregard human intelligence compared to that of idealized aliens that are often just projections of alternate human beings. I can't help but think that the very concept of a founder race or creators is a form of evidence that it's something we'll do when we have the technology.